Walker (elbow, shoulder) believes if he returns to action this season, it will be as a reliever, Nick Piecoro of the Arizona Republic reports.
Walker, who has been working his way back from Tommy John elbow surgery, had a shoulder issue pop up out of nowhere Wednesday. He was back in the Diamondbacks clubhouse Saturday, a day after receiving a platelet-rich plasma injection. "I don't think it would make sense for me to come back and try to ramp up to start," Walker said. The right-hander is hoping to end the season on a positive note, and that might mean throwing out of the bullpen.